Page 10 - classification of elements
P. 10
Valency: The number of electrons that are either lost or
gained or shared by atom during chemical combination is
called valency.
Elements with incomplete outermost shell show tendency
of either loosing or gaining or sharing of electrons.
When outermost shell contains either 2 (for K shell only)
or 8 electrons then outermost shell is said to be fulfilled.
Such elements are said to be reactive elements.
